The Preform and Cold Forging Die Design for a Hollow Bushing Part with Face Gear Features

摘要

In this study, process and cold forging die designs were proposed to make a hollow part with small gear shapes on both ends with a triple-action press. The characteristics of high slenderness ratio, non-uniform hollow part thickness, and small gear shapes on both-ends result in difficulty of die filling and high forging load. First approach, one-pass forging die design was adopted to make all features of the part with an inner web and evaluate the forming difficulty and defects of triple-action forging process. Second approach, a multi-pass process design of two preforms was proposed to make hollow part without small gear shape on open ends. A finish triple-action forging design was proposed to produce the small features on open ends. A flash ring around the small features of the part was designed to improve the material flow of die filling and decrease the forming load. The parameters of preform and finish forging die designs were studied using the FEM simulation processes. The forging experiments were carried out to verify the proposed method, the experiment results showed good agreement with the simulations.